#include <algorithm>
#include <cctype>
#include <functional>
#include <iostream>
#include <istream>
#include <string>
#include <vector>
using ll = int64_t;

std::string s;
std::vector<char> v;

int main(){
    std::iostream::sync_with_stdio(false);
    std::cin.tie(nullptr);

    std::cin>>s;
    v.reserve(s.size());
    for(char c:s){
        if(isdigit(c)){
            v.emplace_back(c);
        }
    }
    std::sort(v.begin(),v.end(),std::greater<>());
    bool isf=true;
    for(char c:v){
        if(isf&&c=='0')continue;
        isf=false;
        std::cout<<c;
    }
    std::cout<<"\n";
}